Snap action switch



Aug. 28, 1956 M. 1.. JEFFREY 2,761,030

SNAP ACTION swncu 2 Sheets-Sheet 1 Filed Feb. 1 195] om @m sm ww mm mm u@e mu v INVENTOR.

NAXLJEFFEEY 28, 1956 M. L. JEFFREY 2,761,030

SNAP ACTION SWITCH Filed Feb. 1, 1951 2 Sheets-Sheet 2 INVENTOR. MAX A.JEFFEEY nited States This invention relates to switches, and moreparticularly to an electrical switch having an improved snap action andcontacts.

In all electrical switches, a primary desideratum is to make andmaintain a low resistance contact between the moving and stationarycontact members. Another aim is low cost of manufacture. The presentedswitch embodying my invention, in large part attains both of these aims,while also utilizing a novel snap action mechanism. This mechanism isoperated by a small movement of the operating lever, and still allows aconsiderable degree of overtravel of the lever so as to prevent damagingthe parts. By utilizing the simple and inexpensive construction I havedevised, a good wiping action is obtained at the contacts which makespossible a close, clean contact between the members. A moderately heavyspring pressure insures the maintenance of good contact.

Because of the sliding action between the contacts it is possible to usea heavier spring for the contacts to maintain a better contact,decreasing contact resistance and, to a greater extent, reduce thepossibility of accidental opening of the contacts in the presence ofshock,

Other advantages of my invention and a full under- I standing thereofmay be had by reference to the following description and the drawingswhich form a part of this specification.

Fig. l is a front elevational the front cover removed;

Fig. 2 is a sectional view of the switch along line 2-2 of Fig. 1;

Fig. 3 is a rear elevational view with the rear lower cover removed;

Fig. 4 is an exploded view of the moving switch parts and rear coverremoved from the housing;

Fig. 5 is a sectional view from line 55 of Fig. l; and

Fig. 6 is a top plan view of the moving contact member.

Briefly, my invention is a switch including a housing into which isfastened a block. The block holds the fixed contacts in place bypressing them against a liner of rubber and fiber on the walls of thehousing, thus eliminating the need for screws or other fasteners in theassembly. The moving contact member is of simple formation, but iscurved transversely so that it slides onto a slanting fixed contactsurface, thus giving a considerable wiping action. The snap action, too,is of inexpensive construction and still is efficient and provides for aconsiderable amount of overtravel of the operating lever to preventbreakage of parts.

More specifically and referring to the figures, the switch is mounted ina housing 10 formed with appropriate mounting lugs 11. A threaded boss12 at the upper end is provided to receive a conduit carrying therequisite electrical leads (not shown) Within the housing an irregularshaped block 14 is mounted and carries the fixed or stationary contactmembers 15 and 15a. These contact members are loosely disposed ingrooves formed in the sides of the block 14 and are held in place bycompression of the members beview of my switch with tween the block 14and bosses 16 formed on the inside of the housing walls. Thiscompression is enhanced by the insulation between the boss and thecontacts which preferably comprises a layer of treated paper 17 and alayer of sheet rubber 18 or rubber-like synthetic material, all of whichmaterials are well known in the art. The block 14 is held in place bybeing disposed over a boss 20 (Fig. 5) formed in the rear wall of thehousing and may be fastened thereto by a screw 21. The customary screws22 for connection of wires to the contacts are provided. However, theholding of the contacts in place in the housing is done solely by theform of the block 14 and the housing 10. In order to facilitateassembly, and to avoid the necessity for drilling the block 14, grooves23 are formed therein extending from the side to accommodate the screws22. To assemble the contacts then, it is necessary only to slide them infrom the side after the screws 22 are in place. Only one screw isnecessary for the complete assembly of the contacts in the housing, andthis screw is in a blind hole inside the housing eliminating the need ofscrew holes through the housing which may cause leakage permittingingress of moisture. It will be readily apparent to those skilled in theart that considerable savings may be realized in the assembly time andin material for this type of a device.

At their lower ends, the contacts are bent away from the sidewalls ofthe housing at an angle which may be approximately 45 degrees. Suitablecontact faces 24 may be sweated or otherwise fixed to the contactmembers.

The moving parts of the switch are best shown in Fig. 4 where they areexploded in the order of their assembly on the shaft 25. The shaft isjournalled in the front lower part of the housing 10 and also .in a boss26 in a rear cover 27. It is held in place in the housing by a keeper 28having a slotted end 29 which engages a groove 30 in the shaft. Thus,with the keeper 28 on one side and an operating lever 32 clamped orotherwise fixed to the shaft on the other side of the housing wall, theshaft is kept from longitudinal movement; An oil seal 31 may be providedwithin the wall of the housing surrounding the shaft.

The driving member 33 of the snap action is keyed to the shaft by keys34 formed thereon and disposed in keyways 35 in the shaft, and is thusadapted to move with the shaft. The driven member 36 is journalled onthe shaft and is of irregular formation. A boss on the member 36,however, is formed similar to the driving member 33. Each has a bodyportion 37 of annular form and a neck 38 extending outwardly therefrom.The member 33 has a head 39 on the neck 38 while the driven member 36 isformed with slanting shoulders 40 to provide a similar shape. A spring42 formed of a plurality of laminations in the shape of a cylinder splitat one radial plane, surrounds the body parts 37 of the driving anddriven members. The split is opened up and the ends 43 of the springengage the neck portions 38 of both the driving and driven members.Thus, any displacement of either member with respect to the other widensthe split between the ends 43 and stores up energy in the spring 42. Thestored energy is effective to snap the contacts as will appearhereinafter. Any tendency of the spring 42 to turn sideways because ofthe displacement angularly between the two members is counteracted bythe keeper plate 28 which holds the spring in line between it and thewall of the driven member 36.

The member 36 is preferably molded of a plastic material such asbakelite or the like and contains a pair of upward extending arms 45preferably formed of metal and molded in the member 36. These arms arebent toward each other at the ends 46 and therefore enclose arectangular opening. The movable contact member 47 is disposed in thisopening and is held in place in part by a spring 48. Adjacent theshoulders 40, the member 36 is formed with a ledge 49 overhanging thehead 39 of this drive member 33 and adapted to engage the edge of thekeeper 23 to hold it in position on the shaft (Fig. 2).

The contact member 47 (Fig. 6) is substantially H-shaped having a crossmember 50 and two slide members 51. The side members are both bowed inthe form of a cylinder whose axis is parallel to the cross member 50. Ateach of the four ends of the side members, contact face pieces 52 areattached in position to engage the fixed contact faces 24. The movablecontact member is assembled by inserting the edge of the cross member 50between the ends 46 of the arms 45 and inserting the membertherebetween. The sides 51 engaging the arms 45 prevent axial movementof the member. The driven member 36 is formed with a dished shape at 53(Fig. l) to match the cylindrical form of the contact member 47. Thespring 48 presses the contact member 47 into this seat. A dimple 54 isformed on the contact member, and a part of the ends 46 of the arms 45are either struck down or dimpled at 55 to extend into the spring andlocate it properly.

As is best shown in Fig. l, the contact member 47 is adapted to slide upon the fixed contacts 15 and 15a as the switch is thrown. As the facepiece 52 first engages the face 24 on the fixed contacts, the member 47rocks out of the hollowed surface 53. As the motion is continued, thetwo faces 52 and 24 slide over each other providing the desired wipingaction on bringing of the two surfaces together which improves theconductance of the contact. Also as the movable contacts ride up on thesloping fixed contacts, the spring 48 is compressed, thus furtherimproving the characteristics of the contact. This operation enables theuse of a stiffer spring 48 to thus provide a strong contact pressure.

A flange member 56 is journalled on the shaft 25 adjathe driven memberand is held in fixed relation to that member by the engagement of a pairof fingers 57 engaged in slots 58 formed in the driven member 36. Aflange 59 formed on this member 56 extends over the next adjacent piece,the cam member 60. This latter member 60 is formed to provide keys 62which are engaged in the keyways 35 in the shaft so that the member 60is driven by the shaft. A pair of stops 63 are also formed on the member66 for a reason to be made obvious hereinafter. Adjacent the flange 59,a pair of rising cams 64 are formed, rising to a continuous dwell 65between the cams.

As is best illustrated in Fig. 3, these cams are effective to releasethe snap action to permit quick motion of the switching elements.Holding the snap action to prevent premature motion are a pair ofsimilar latches 66 journalled on pins 67. The pins 67 are held in holesin bosses 68 in the housing and are prevented from sliding out of theholes by bottoming in holes in bosses 69 formed on the rear cover 27(Fig. 4). The bosses 68 and 69 are proportioned so that the latches 66are positioned therebetween in the plane of the flange 59. The ends 70of the latch then are in position to engage this flange to preventmotion. Springs 72 engaged between the housing and the latches 66 andheld by projecting parts 73 urge the latches around the pins intoengagement with the flange 59.

Follower arms 74 are engageable by the rising cams 64 to release theholding. Since the latches are on the housing, and the cam member 60 iskeyed to the shaft, it is apparent that the shaft must move in thehousing to release the latches. However, the flanged member 56 which iskeyed to the contact carrier 36 is held in fixed relation to the housingby the latch. There must be relative movement therefore between theshaft 25 and the contact carrier 36. In the preferred embodiment thismotion is of the order of degrees of angular motion.

The relative motion stores energy in the spring 42 cient to cause arapid snap of the contact carrier 36 upon release of the appropriatelatch. Because the latches are fixed in relation to the housing, afterthe cam 64 has engaged the latch and the flange 59 has been released,the latch does not become re-engaged or cocked again, as it might inthose switches where the latches are carried by the moving contactcarrier. This results in a freedom of movement in the same direction forthe operating lever 32 not found in other snap action devices. Forexample, in the embodiment shown, the lever 32 is free to turn the shaft25 for 15 degrees clockwise beyond the normal position shown in Fig. 3.The same degree of freedom is allowed in the other direction after theswitch has been snapped. Thus there is considerable freedom forovertravel of the lever 32, and this travel is limited only by theengagement of the stops 63 with abutments 75 on the housing.

The shaft of the switch may be biased to either one or the other side bya coil spring 78 which, at one end 79, is hooked over a foot 80 bentfrom the cam member 6%. The other end 81 may be engaged in any of aplurality of slots 82 cut in the boss 26 on the rear cover. Thus, thetension of the spring may be altered by changing the end 81 from oneslot to another, and merely by reversing the spring, the direction ofbias of the shaft may be reversed.

It will be appreciated that in some instances it may be desirable toeliminate the spring where the switch is used for manual operations andto enable the contacts to be held in either of their alternate lockedpositions.

' It will also be apparent that the curvature of the movable contactmember may be exactly opposite to that shown, in which event the angularrelation of the fixed contacts would be changed to provide the propercontact. In this instance, the spring 48 would be underneath the movablecontact pressing it against the arms 46.

Thus it is apparent that by my invention, I am able to provide aninexpensive snap action switch, which is very flexible. Provision ismade for considerable overtravel of the operating lever, and thecontacts are of such formation that lessened contact resistance resultstherefrom.

Having thus described my invention, 1 am aware that numerous andextensive departures may be made therefrom without departing from thespirit or scope of my invention.

I claim:

1. A switch comprising a housing, an insulating block disposed in saidhousing, fixed contacts compressively held between said block and saidhousing, said contacts having contact surfaces extending away from thewalls of said housing at an oblique angle thereto, a contact carrierincluding a block member pivotally journalled in said housing, a pair ofangular arms extending from said block member and enclosing arectangular opening therewith, a movable contact member having a crossmember disposed in said opening and side members adapted to engage saidarms to retain said movable member, a spring engaged between said armsand said movable member to urge said movable member towards said blockmember, said movable contact member being formed with arcuate contactsurfaces, said carrier being adapted to move said movable contactsurfaces into and out of engagement with said fixed contact surfaces,and said block member engaging said movable contact member upon pivotalmovement of said contact carrier and being operable to slide saidarcuate contact surfaces tangentially relative to said fixed contactsurfaces upon initial engagement of said contact surfaces.

2. In a switch having a housing, fixed contacts mounted in said housing,and movable contacts adapted to bridge said fixed contacts; snap actionmeans comprising a shaft journalled in said housing, a contact carriermember adapted to carry said movable contacts journalled on said shaft,a driving member keyed to said shaft adjacent said carrier member, saidcarrier member and driving member both being formed with similar bodyportion and neck portions extending from said body portions, a springdisposed about said body portions and engaging said neck portions, saidspring being adapted to store energy upon displacement between saidcarrier member and said driving member, a flange member keyed to saidcarrier member having a flange extending away from said carrier, a cammember keyed to said shaft adjacent said flange member and under saidflange, latch members pivotally mounted in said housing having armsadapted to engage said flange in a holding relationship, followermembers on said latch members adapted to engage said cam member, saidcam member being formed to provide cams, said follower when moved bysaid cams being adapted to release said flange to allow said carriermember to be snapped to a second position.

3. In a switch having a housing, fixed contacts mounted in said housing,and movable contacts adapted to bridge said shaft, a driving memberkeyed to said shaft adjacent said carrier member, said carrier memberand driving member both being formed with similar body portion and neckportions extending from said'body portions, a spring disposed about saidbody portions and engaging said neck portions, said spring being adaptedto store energy upon displacement between said carrier member and saiddriving member, a flange member keyed to said carrier member having aflange extending away from said carrier, a cam member keyed to saidshaft adjacent said flange member and under said flange, latch memberspivotally mounted in said housing having arms adapted to engage saidflange in a holding relationship, follower members on said latch membersadapted to engage said cam member, said cam member being formed toprovide cams, said follower when moved by said cams being adapted torelease said flange to allow said carrier member to be snapped to asecond position, said cam member being formed with a foot thereon, and aspring engaged between said foot and said housing to bias said shaft ina predetermined direction.

4. In a switch having a housing, fixed contacts mounted in said housing,and movable contacts adapted to bridge said fixed contacts; snap actionmeans comprising a shaft journalled in a front wall and in a rear bossin said housing, a movable contact carrier member journalled on saidshaft, means engaged between said carrier and said shaft adapted tostore up energy upon relative movement therebetween, holding means fixedto said carrier member, latch means pivotally mounted on said housing inposition to engage said holding means, latch release means on said shaftadapted to release said latch means upon a predetermined rotation ofsaid shaft, said boss being formed with a plurality of radial slotstherein, and a coiled spring operably connected to said shaft and havingone end engaged in one of said slots to bias said shaft in a certaindirection.

5. In a switch having a housing, fixed contacts mounted in said housing,and movable contacts adapted to bridge said fixed contacts; snap actionmeans comprising a shaft journalled in a front wall and in a rear bossin said housing, a movable contact carrier member journalled on saidshaft, means engaged between said carrier and said shaft adapted tostore up energy upon relative movement therebetween, holding means fixedto said carrier member, latch means pivotally mounted on said housing inposition to engage said holding means, latch release means -on saidshaft adapted to release said latch means upon a predetermined rotationof said shaft, said boss being formed with a plurality of radial slotstherein, and a coiled spring operably connected to said shaft and havingone end engaged in one of said slots to bias said shaft in a certaindirection, said spring being reversible in said slots to reverse thedirection of bias.

6. In a switch having a housing, fixed contacts mounted in ,saidhousing, and movable contacts adapted to complete an electrical circuitbetween said fixed contacts; snap action means comprising a shaftjournalled in said housing, a carrier member adapted to carry saidmovable contacts journalled on said shaft, means engaged between saidcarrier member and said shaft adapted to store energy upon displacementtherebetween, holding means fixed to said carrier member, latch meanspivotally mounted in said housing adapted to engage said holding meansat a predetermined position of said carrier member, release means onsaid shaft adapted to engage said latch means as said shaft is turned torelease said latch means, abutment means formed on said housing adjacentsaid release means, and stop means on said release means adapted to stopthe travel of said shaft at a point beyond the point of release of saidlatch means by engagement with said abutment means.

7. In a switch having a housing with a rear cover, fixed contactsmounted in said housing, and movable contacts adapted to be carriedtoward said fixed contacts to complete an electrical circuittherebetween; snap action means comprising a shaft journalled in thefront wall of said housing and in a boss on said rear cover, anoperating lever fixed to said shaft, a contact carrier member adapted tocarry said movable contacts journalled on said shaft, said member beingformed with a body part surrounding said shaft and a neck part extendingfrom said body part, a driving member keyed to said shaft formed with asimilar body'and neck part, said body and neck parts on the driving andcarrier member being normally in alignment, a leaf-type springsurrounding said body parts and having ends engaging said neck parts, akeeper rotatably movable but longitudinally fixed on said shaft adjacentsaid driving member, said keeper being formed and positioned to holdsaid spring aligned with said members, said carrier member being formedto engage said keeper to hold it on said shaft, a flange member keyed tosaid carrier member and having a flange extending away from said carriermember, a cam member keyed to said shaft formed to provide cam surfacesbeneath said flange, latch members pivotally mounted in said housinghaving arms adapted to engage said flange to hold said flange memberrelative to said housing, said latch members also being formed with afollower part in position to be engaged by said cam surfaces to releasesaid latch from said flange upon a predetermined amount of rotation ofsaid shaft, said cam member also being formed with stop surfaces,abutment members formed in said housing in position to be engaged bysaid stop surfaces at a point substantially beyond the point of. releaseof said latch member, and a spring engaged between said cam member andsaid rear cover to bias said shaft in one direction.

8. A switch comprising a housing, a shaft rotatably journalled inopposite walls of and bridging the housing, pairs of fixed contacts eachpair adapted to be bridged by movable contacts and supported on oppositesides of the housing, a movable contact carrier journalled on saidshaft, and snap mechanism cooperating with said shaft, housing andcontact carrier to swing said contact carrier quickly upon apredetermined movement of said shaft, said contact carrier including aportion extending laterally from the shaft and swingable between thefixed contacts, and having a pair of spaced guide arms on its endsprovided with end portions extending inwardly toward each other to forman abutment, said carrier being formed to provide an arcuate seatopposite said abutment; said movable contact comprising a portiondisposed between said guide arms and extending beyond the confines ofthe guide arms and provided with portions extending laterally of thecarrier and having contacts on their ends disposed on each side of thecarrier, said contact 7 member being arcuately curved and spring meansbetween the abutment and the contact member to hold it onto said arcuateseat, said fixed contacts on each opposite side of the housing extendinginwardly from the sidewalls in a plane which is tangent to the arcuatesurface of said contact member when said contacts are contacting eachother, said contact carrier being swingable to swing said contact memberinto circuit closing engagement with each of said pairs of oppositelydisposed fixed contacts and upon engagement therewith, said springcompressing and permitting tipping of the contact member on the seat,said movable contacts engaging said fixed contacts upon swinging of saidcarrier to slide the movable contacts onto the fixed contacts.

9. A switch including a housing with fixed contacts supported onopposite sides thereof, a contact carrier having movable contact carriermeans for engagement with said fixed contacts and operating means forsaid movable contact means comprising a slotted shaft journalled inbearings in the front and rear of the housing, said contact carrierbeing freely journalled on said shaft and including a base having a bossformed on one side thereof with a neck extending from the periphery,means for communicating movement from the shaft to said carrierincluding an operating lever including a body surrounding said shaft andhaving at leastone lug in one of said slots, said lever having a neckjuxtaposed to the neck and said boss and spring means engaging saidnecks on opposite sides to hold them in alignment, means for boldingsaid shaft against movement comprising a flange member surrounding theshaft and having lugs engaging said carrier member on opposite sides fordriving engagement therewith and a pawl engaging flange, pawls pivotallysupported on the opposite sides of said housing and having portions foralternate engagement with said flange and spring means for moving saidpawls into engagement with said flange, cam means surrounding said shaftand having at least one lug interlocked in said groove and a cam surfaceon said cam arranged for alternate engagement with said pawls to releasesaid pawls upon movement of the shaft.

10. In a switch having a housing, fixed contacts mountcd'in saidhousing, and movable contacts adapted to bridge 8 said fixed contacts;snap action means comprising a shaft disposed in said housing, a contactcarrier member adapted to carry said movable contacts disposed on saidshaft, a driving member disposed adjacent said carrier member, saidcarrier member and driving member both being formed with portions thatare adjacent to and in alignment with and movable relative to eachother, a spring means engaging said aligned portions to hold them inalignment said portions being movable out of alignment against thepressure of the spring said spring being adapted to store energy upondisplacement between said carrier member and said driving member, amember keyed to said carrier member having a part extending away fromsaid carrier, a cam member keyed to said shaft adjacent said member andadjacent said part, latch members pivotally mounted in said housinghaving arms adapted to engage said part in a holding relationshiptherewith, follower members on said latch members adapted to engage saidcam member, said cam member being formed to provide cams, said followerwhen moved by said cams being adapted to release said part to allow saidcarrier member to be snapped to a second position by said spring.

References Cited in the file of this patent UNITED STATES PATENTS1,215,423 Spengler Feb. 13, 1917 1,945,819 Millermaster Feb. 6, 19342,115,069 Hall Apr. 26, 1938 2,269,171 Benander Jan. 6, 1942 2,273,545Van Valkenburg Feb. 17, 1942 2,289,086 Van Valkenburg July 7, 19422,294,559 Jeffrey Sept. 1, 1942 2,416,626 Jeffrey Feb. 25, 19472,418,068 Cornelius Mar. 25, 1947 2,429,812 Hausler Oct. 28, 19472,491,696 Venditty Dec. 20, 1949 2,523,370 Jefirey Sept. 26, 19502,542,088 Krieger Feb. 20, 1951 2,581,705 Riche Jan. 8, 1952 2,614,196Wilson Oct. 14, 1952 FOREIGN PATENTS 391,323 Great Britain Apr. 27, 1933

